fix(ts): match MiddlewareConfig with documentation (#61718)

### What?

Fix the user-facing `MiddlewareConfig` interface.

~While in the codebase, I also made the incoming config object type a
bit more strict by converting from `any` to `unknown`.~ Reverted, as we
do a config assertion already in a [different
place](https://github.com/vercel/next.js/blob/canary/packages/next-swc/crates/next-custom-transforms/src/transforms/page_config.rs/#L171-L180).

### Why?

The interface we previously exposed was the one we used internally,
_after_ we did some parsing on the config object, which is different
from what the user is expected to pass.

### How?

I separated the internal type to its own `MiddlewareConfigParsed`
interface.

Closes NEXT-2375
Fixes #61705

Ref: #61576

packages/next/src/build/analysis/get-page-static-info.ts

@@ -24,13 +24,22 @@ import { PAGE_TYPES } from '../../lib/page-types'
 // Don't forget to update the next-types-plugin file as well
 const AUTHORIZED_EXTRA_ROUTER_PROPS = ['maxDuration']
 
-/** @see https://nextjs.org/docs/app/api-reference/file-conventions/middleware#config-object-optional */
+export interface MiddlewareConfigParsed
+  extends Omit<MiddlewareConfig, 'matcher'> {
+  matchers?: MiddlewareMatcher[]
+}
+
+/**
+ * This interface represents the exported `config` object in a `middleware.ts` file.
+ *
+ * Read more: [Next.js Docs: Middleware `config` object](https://nextjs.org/docs/app/api-reference/file-conventions/middleware#config-object-optional)
+ */
 export interface MiddlewareConfig {
   /**
-   * @see https://nextjs.org/docs/app/api-reference/file-conventions/middleware#matcher
-   * @see https://nextjs.org/docs/app/building-your-application/routing/middleware#matching-paths
+   * Read more: [Next.js Docs: Middleware `matcher`](https://nextjs.org/docs/app/api-reference/file-conventions/middleware#matcher),
+   * [Next.js Docs: Middleware matching paths](https://nextjs.org/docs/app/building-your-application/routing/middleware#matching-paths)
    */
-  matchers?: MiddlewareMatcher[]
+  matcher?: string | string[] | MiddlewareMatcher[]
   unstable_allowDynamicGlobs?: string[]
   regions?: string[] | string
 }
@@ -50,7 +59,7 @@ export interface PageStaticInfo {
   ssr?: boolean
   rsc?: RSCModuleType
   generateStaticParams?: boolean
-  middleware?: MiddlewareConfig
+  middleware?: MiddlewareConfigParsed
   amp?: boolean | 'hybrid'
   extraConfig?: Record<string, any>
 }
@@ -377,8 +386,8 @@ function getMiddlewareConfig(
   pageFilePath: string,
   config: any,
   nextConfig: NextConfig
-): Partial<MiddlewareConfig> {
-  const result: Partial<MiddlewareConfig> = {}
+): Partial<MiddlewareConfigParsed> {
+  const result: Partial<MiddlewareConfigParsed> = {}
 
   if (config.matcher) {
     result.matchers = getMiddlewareMatchers(config.matcher, nextConfig)
@@ -508,14 +517,14 @@ export async function getPageStaticInfo(params: {
     const rsc = rscInfo.type
 
     // default / failsafe value for config
-    let config: any
+    let config: any // TODO: type this as unknown
     try {
       config = extractExportedConstValue(swcAST, 'config')
     } catch (e) {
       if (e instanceof UnsupportedValueError) {
         warnAboutUnsupportedValue(pageFilePath, page, e)
       }
-      // `export config` doesn't exist, or other unknown error throw by swc, silence them
+      // `export config` doesn't exist, or other unknown error thrown by swc, silence them
     }
 
     const extraConfig: Record<string, any> = {}

packages/next/src/build/entries.ts

@@ -5,6 +5,7 @@ import type { EdgeAppRouteLoaderQuery } from './webpack/loaders/next-edge-app-ro
 import type { NextConfigComplete } from '../server/config-shared'
 import type { webpack } from 'next/dist/compiled/webpack/webpack'
 import type {
+  MiddlewareConfigParsed,
   MiddlewareConfig,
   MiddlewareMatcher,
   PageStaticInfo,
@@ -332,7 +333,7 @@ export function getEdgeServerEntry(opts: {
   isServerComponent: boolean
   page: string
   pages: MappedPages
-  middleware?: Partial<MiddlewareConfig>
+  middleware?: Partial<MiddlewareConfigParsed>
   pagesType: PAGE_TYPES
   appDirLoader?: string
   hasInstrumentationHook?: boolean

test/production/middleware-typescript/app/middleware.ts

@@ -24,8 +24,8 @@ export const middleware: NextMiddleware = function (request) {
   }
 }
 
-export const config: MiddlewareConfig = {
-  matchers: [],
+export const config = {
+  matcher: [],
   regions: [],
   unstable_allowDynamicGlobs: undefined,
-}
+} satisfies MiddlewareConfig